Tie rod load indicator



May 26,1970 G. F. BOWDEN E'IAL 3,513,803

TIE ROD LOAD INDICATOR Filed Nov. 25. 1968 3 Sheet s -Sheet l lNVE/VTORSGEORGE E BOWDEN y DAV/D L. C Y

Afrorney May 26, 1970 G. FQBowDEN ETAL 3,513,303

TIE ROD LOAD INDICATOR Filed Nov. 25, 1968 :5 Sheets-Sheet 2 soIIVVENTORQ 650/?65 BOWDEN DA W0 1.. copy Attorney May 26, 1970 s. F.BOWDEN ETAL 3,513,803

TIE ROD-LOAD INDICATOR 3 Sheets-Sheet 5 Filed Nov. 25. 1968 FIG. 5

lNl/EN7'0R5 GEORGE F. BOWDE/V DA V/D L. 7 y 54 9.4

Attorney Fla. 6

United States Patent 3,513,803 TIE ROD LOAD INDICATOR George F. Bowden,Northbrook, and David L. Cody,

Hoffman Estates, 11]., assignors to Symons Mfg. Company, Des Plaines,111., a corporation of Delaware Filed Nov. 25, 1968, Ser. No. 778,410Int. Cl. G01d 21/00 US. Cl. 116114 6 Claims ABSTRACT OF THE DISCLOSURE Atie rod load indicator which is designed for attachment to one of thecrossbars of a wall form panel and measures the deflection of suchcrossbar under the influence of the pressure of the wet concrete whichis poured against the facing of the panel, crossbar deflection being adirect function of the tension attained in the adjacent tie rods. Anovel linkage mechanism magnifies the crossbar deflection and renders avisual indication of such deflection by means of a scale-and-pointerassembly which is visible through a window opening provided in a boxlikehousing which encloses the working parts of the indicator.

The present invention relates to a tie rod load indicator for measuringthe deflection which takes place in the metal studding of a concretewall form panel when the plywood or other facing of such panel issubjected to outward bulging under the tremendous thrust of the wetconcrete which is poured against the panel during normal intended use ofthe latter. Specifically, the invention is concerned with a tie rod loadindicator of the general type which is shown and described in copendingUS. patent application Ser. No. 539,112, filed on Mar. 11, 1966 andentitled Tie Rod Load Indicator (now US. Pat. No. 3,467,054, dated Sept.16, 1969), and over which the present tie rod load indicator is animprovement.

In a concrete wall form installation, where a series of rectangular wallform panels are arranged in edge-t0- edge relationship and also inopposed relation with a similar series of panels in order to form thespaced apart sides of the installation and to receive between it and theother series poured wet concrete for wall forming purposes, thehorizontally and transversely extending tie rods which connect the twosides of the installation are subjected to extremely high tensionalforces which progressively increase in proportion to a certain algebraicpower of the height of the mass of the wet concrete as it is beingpoured. If concrete pouring operations are continued indiscriminately,rupture of the tie rods will, of course, take place. Therefore, it iscurrent practice to calculate according to certain mathematicalconsiderations the safe height to which one of successive batches of wetconcrete may be poured for a given concrete wall installation, takinginto consideration the safe height to which the wet concrete may bepoured before the danger point is reached and it is hence necessary todiscontinue pouring until the poured concrete has hardened sufiicientlyto justify a resumption of concrete pouring operations. Thesemathematical considerations involve such factors as the number andplacement of the tie rods, the distance between the opposed and spacedapart sides of the concrete wall form installation, the fluidity of thewet concrete, the known rigidity of the panels, as well as other factorsof a varied nature. By the successive pouring of superimposed lifts" orbatches of concrete to predetermined or calculated safe heights, dangerof tie rod rupture may be effectively avoided.

The load indicator of the present invention makes possible a method ofconcrete pouring in connection with 3,513,803 Patented May 26, 1970 theerection of a concrete wall wherein the deflection of the metal studdingof the wall form panels is correlated with the tie rod load and suchdeflection is measured so that each successive concrete pouringoperation may be terminated at a given location or height in theinstallation when a predetermined amount of deflection representing themaximum safe tension or load on the tie rods has been attained.

The tie rod load indicator of the present invention finds particular usein connection with a concrete wall form installation which employ panelsof the Steel-Ply type. A Steel-Ply panel consists essentially of ashallow traylike structure including a rectangular plywood or otherfacing, the edges or marginal portions of which are completely encasedin a metal rectangular reinforcing frame comprising transverse andlongitudinal frame members, together with a normally vertical series ofparallel spaced apart transverse crossbars which extend between thelongitudinal frame members and lend reinforcement to the medial orcentral regions of the facing by constituting a backing therefor.Although the tie rods which extend between the two opposed and spacedapart sides of a concrete wall form installation are ordinarilyconnected to the sides at the juncture regions between adjacent panelsso that the load on any given tie rod is a function of the tensionalforces which are applied to the tie rod between such juncture regions,it is recognized that the localized deflection of the crossbars bears apredetermined relationship to the load which is applied to the tie rodsin the vicinity of such crossbars. Therefore, if pouring operations areso conducted that the deflection of a given crossbar is maintained belowa predetermined safe maximum deflection, the load upon the tie rods inthe vicinity of such crossbar may be kept within safe limits. Thepresent tie rod load indicator is in the form of a novel apparatus ordevice the design and use of which are predicated upon this principle ofcrossbar deflection measurement and consequent tie rod tensionindication.

In carrying out the principles of the present invention, there isprovided a novel tie rod load indicator which is in the form of aself-contained compact device or unit which is capable of being quicklyattached to or removed from one of the crossbars of a concrete wall formpanel of the Steel-Ply type and, when thus applied, progressivelymeasures the deflection of such crossbar while the concrete is beingpoured against the plywood facing of the panel. A pointer and scaleassembly in associated relation with, and forming a part of, theindicator gives a visual indication of the amount of deflection of theinvolved crossbar and certain markings on the scale are so calibrated asto indicate when a maximum safe tie rod tension or load has beenattained so that an active concrete pouring operation in the vicinity ofthe crossbar to which the indicator is applied may be terminated. Morespecifically, the tie rod load indicator of the present inventioncomprises a rigid shallow tray-like housing or rectangularconfiguration, one Wall of which constitutes a reaction plate whichcarries at adjacent corners thereof a pair of clamps by means of whichthe plate may be secured at widely spaced points to the medial region ofa crossbar in edge-to-edge relationship with the plate lying generallyin the horizontal plane of the crossbar and in overhanging relationship.A springbiased pointer, having its proximate end pivoted to the platefor swinging movement across the general horizontal plane thereof, hasits distal end visible through an opening or window in the plate, thepointer cooperating visually with a scale which traverses the window andmay be stencilled, printed, or in the form of a decalcomania, on thetransparent window pane. The proximate region of the pointer is designedfor sliding contact with the distal end of a beam-engaging lever theproximate end of such lever being pivoted to the plate and the levermaking effective contact with the central portion of the crossbar underthe influence of concrete pressure against the associated plywood facingis greatly magnified by corresponding swinging movements of the leverand the pointer and the position of the latter with respect to thewindow-covered scale may readily be visualized. The aforementioned platewhich serves as a mount for the two crossbar-engaging clamps, thepointer and the lever, constitutes one major, mechanism-supporting sideof the generally flat shallow rectangular tray-like housing, the othermajor side of the housing being in the form of a removable cover platewhich conceals the working mechanism of the indicator and, incombination with the mechanism-supporting plate, encloses and protectsthe operative moving parts of the indicator.

The present tie rod load indicator is capable of being clamped to agiven crossbar in its normal horizontal position with thewindow-carrying plate facing either upwordly or downwardly as desired.When applied to a crossbar which lies below the eyes of an observer,i.e., within four or five feet from the ground level, the indicator willbe clamped to the crossbar with the window opening facing upwardly sothat the pointer may readily be viewed from above. If the crossbar isdisposed at a level which lies above the eyes of the observer, theposition of the indicator will be reversed so that the window facesdownwardly for viewing from below. In either situation, the operation ofthe indicator is not altered. Finally, means are provided whereby thepivot point for the pointer may be varied or adjusted within smalllimits to re-adjust the movements of the pointer so that they willconform to the calibration of the scale if for any reason the originalfactory-adjustment is disturbed.

The provision of a tie rod load indicator such as has been brieflyoutlined above and possessing the stated advantages constitutes theprincipal object of the present invention.

Numerous other objects and advantages, not at this time enumerated, willreadily become apparent as the nature of the invention is betterunderstood from a consideration of the following detailed description.

The invention consists in the several novel features which arehereinafter described and more particularly defined by the claims at theconclusion hereof.

'In the accompanying three sheets of drawings forming a part of thisspecification, one illustrative embodiment of the invention is shown,together with a disclosure of the manner in which it is employed inconnection with a concrete pouring operation.

In these drawings:

FIG. 1 is a fragmentary perspective view of a portion of a conventionalconcrete wall form installation, illustrating the manner in which thepresent tie rod load indicator is attached to one of the crossbars ofone of the wall form panels of the installation;

FIG. 2 is an exploded top perspective view of the tie rod loadindicator;

FIG. 3 is a top perspective view showing the assembled tie rod loadindicator operatively applied to a panel crossbar, portions of theindicator housing being broken away in the interests of clarity;

FIG. 4 is a horizontal sectional view taken on the horizontal planerepresented by the line 44 of FIG. 3 and in the direction of the arrows;

FIG. 5 is a sectional view taken substantially on the line 5-5 of FIG.4; and

FIG. 6 is a sectional view similar to FIG. 5 but showing the conditionof the indicator when the crossbar to which it is attached is under anappreciable concrete load due to the pouring of concrete against theadjacent plywood facing.

Referring now to the drawings in detail and in particular to FIG. 1, aconventional concrete wall form installation is designated in itsentirety by the reference numeral 10 and involves in its generalorganization two series 12 and 14 of rectangular concrete wall formpanels 16, the panels of each series being arranged in upstanding andedge-to-edge relationship and forming one side of the installation. Thepanels 16 of the two series are maintained in spaced parallel relationby means of horizontal, transversely extending tie rods 18, two such tierods being illustrated as being associated with two adjacent panels ofeach series in the production of the concrete wall which is to be formedby pouring of wet concrete between the two sides of the installation 10.

The various panels 16 are of the prefabricated Steel- Ply type, which isto say that they consist of rectangular plywood facings 20 andrectangular steel studding or reinforcing frames around the edges of thefacings 20. The reinforcing frame of each panel 16 consists of verticalframe members 22 and horizontal frame members 23. At appropriate levelsin the concrete form installation, suitable crossbars 24 of angle shapedesign extend across the outer faces of the panel facings 20 and betweenthe vertical frame members 22.

Specifically, the vertical frame members 22 are in the form ofstructural steel bars which are generally of shallow U-shape crosssection and include spaced marginal parallel ribs 26 and 28 andconnecting web portions 30. Such ribs extend outwards from the webportions 30. On the side of each web portion 30, that is, opposite tothe ribs 26 and 28, is a shallow longitudinally extending rib 32 whichprojects inwards and defines an annular groove or recess for receptiontherein of the adjacent vertical edge region of the associated plywoodfacing 20. The horizontal crossbars 24 have the ends thereof welded orotherwise fixedly connected to the inside faces of the web portions 30of the vertical frame members 22. At vertically spaced regions along thevertical frame members 22, the ribs 26 and 28 are provided with notches34 to accommodate the end portions of the tie rods 18, while the webportions 30 of the vertical frame members 22 are formed with rectangularslots 36. These slots are in horizontal register with the notches 34 andare adapted for reception therethrough of the bolts of conventionalconnecting bolt and wedge assemblies 38 by means of which adjacent wallform panels are fastened together, all in a manner that is well known inthe concrete wall construction art.

The tie rods 18 are each in the form of a length of fiat sheet metalstock of rectangular cross section and of a longitudinal extentappreciably greater than the over-all width of the spaced series 12 and14 of panels 16. Spaced apart slots 44 are formed in the end portions ofthe tie rods 18 for selective register with the slots 36 in the Webportions 30 of the vertical frame members 22 when the concrete wall forminstallation is assembled, to the end that the bolts of the bolt andwedge assemblies 38 may cooperate with the slots 36 and 44 in securingthe end portions of the tie rods 18 in position between adjacent panels16.

It will be apparent that when wet concrete is poured between the twospaced apart sides of the concrete wall form installation 10, that is,the series 12 and 14 of connected panels 16, the horizontally disposedtie rods 18 will be placed under tension and that the pouring of eachlift or batch of wet concrete must be terminated in a given region ofthe installation before the maximum safe load on the tie rods in thevicinity of pouring operations is exceeded. When wet concrete is pouredbetween the two series 12 and 14 of panels, not only does outwardbulging take place due to the lateral forces which are applied to theform installation at the juncture regions between adjacent panels, butbulging of the plywood facings of the individual panels takes place andis restrained by the existence of the crossbars 24. As a consequence,these crossbars are subject to lateral outward deflection or bending.Therefore, the amount of lateral deflection which takes place in anygiven crossbar 24 is a fairly accurate measure of the tension which hasbeen attained in the adjacent tie rods 18, this tension depending ofcourse, upon the number of employed tie rods, the greater the number oftie rods, the greater the load which these tie rods, consideredcollectively, will withstand. In order to measure the deflection of agiven crossbar 24, there is provided, according to the presentinvention, a novel tie rod load indicator which is capable of beingquickly and easily applied to and removed from a selected crossbar 24.

Referring now additionally to FIGS. 2 to 6, inclusive, the tie rod loadindicator 50 of the present invention involves in its generalorganization a two-part flat rectangular housing of comparatively smallthickness and comprising two separable parts, namely, a base part 52 anda cover part 54. In the position in which the in dicator 50 is shown inFIGS. 2, 3 and 4, the base part is the upper part while the cover partis the lower part which fits within the upper part in telescopicrelationship. Considering the base part 52 in its thus illustratedposition, it is in the form of a rectangular plate 56 having threedownturned marginal flanges including a longitudinally extending sideflange 58 which extends along the outer longitudinal edge of the plate,and opposed end flanges 60 and 62 which extend along the transverse endedges of the plate 56. The plate 56 constitutes the top wall of the basepart 52 of the indicator housing and it serves operatively to supportall of the operating parts of the tie rod load indicator 50.

The cover part 54 also is in the form of a rectangular plate 64 (seeparticularly FIG. 2) having three upturned marginal flanges including alongitudinally extending side flange 6-6 and two opposed end flanges 68and 70. The three flanges 66, 68 and 70 fit within the three flanges 58,60 and 62 of the base part 52 as shown in FIG. 3, the two plates 56 and64 remaining spaced apart a slight distance so that the thus assembledhousing is of flat rectangular design and presents one open side, i.e.,the side opposite the side which is defined by the side flanges 58 and66. It is to be noted that the cover part 54 which, as aforementioned,is telescopically received within the confines of the base part 52, doesnot support or cooperate in any manner with the various movabledeflection-measuring instrumentalities which are entirely supported fromthe base part 52. The function of the cover part 54 is solely to enclosethese instrumentalities and shield them, both when the indicator 50 isin use, and during handling, shipment, or storage thereof.

As shown in each of FIGS. 2 to 6, inclusive, two flange clamps ofC-shape configuration and having clamping screws 81 associated therewithare disposed adjacent to the two corners of the plate 56 which aredisposed near the open side of the housing, and are adapted to befixedly secured to the end regions of a selected crossbar 24 as shown inFIGS. 1, 4, 5 and 6, preferably with the flange clamps presenting anequal spacing with respect to the adjacent vertical frame members 22 ofthe associated panel 16. For reasons that will be made clear presently,such attachment of the flange clamps 80 to a given crossbar in aconcrete wall form installation such as is illustrated in FIG. 1 may bemade with the tie rod load indicator as a whole assuming a horizontalposition with either the base part 52 or the cover part 54 facingupwardly. The upper leg portions of the flange clamps 80 are preferablywelded to'the adjacent corner portions of the plate 56 of the basehousing part 52.

Considering again the construction of the base part 52, the rectan ularplate 56 of such part is provided with a rectangular window opening 82in the right-hand region thereof as viewed in FIGS. 2 and 3 and in theleft-hand region thereof as viewed in FIGS. 5 and 6. A glass or othertransparent pane 84 extends across the window opening and has appliedthereon a scale 86 which may be calibrated in any desired manner withsuitable indicia having reference to the amount of cross bar deflectionwhich takes place during concrete-pouring operation. The

scale 86 is designed for cooperation with a pointer 90. The latter hasassociated with it a magnification linkage mechanism which is designatedin its entirety by the reference numeral 92 in FIGS. 3 to 6, inclusive,and is supported solely from the plate 56 of the housing base part 52.

The pointer is in the form of an elongated rod, the proximate end regionof which projects completely through at laterally adjustable pivot block94 and is fixedly secured in the block by soldering, brazing or thelike. The block '94 is loosely mounted for angular turning movement in ahorizontal plane about the axis of a shouldered pivot pin 96 which iscapable of being clamped in selected adjusted positions along a slot 98in the plate 56. The extreme proximate end of the pointer 90 is suitablyattached to one end of a helical tension spring 100 and the other end ofthe spring is secured to the downturned end flange 62 on the plate 56 ata point where the tension in the spring will yielding-1y urge thepointer 90 in a counterclockwise direction as viewed in FIGS. 2 and 3and in a clockwise direction as viewed in FIGS. 5 and 6. The distal endregion of the pointer 90 is guided between a bar-like strap 102 and theplate 56, while the extreme distal end of the pointer traverses thescale 86. A series of four nut and bolt assemblies 104 serves to holdthe transparent pane 84 in position over the window opening '82 and twoof these assemblies also serve to hold the strap 102 in spaced positionon the underneath or bottom side of the plate 56 of the base housingpart 52.

The linkage mechanism 92 further includes thrust means in the form of asecond class lever 110, the proximate end of which is pivoted by avertical pin 112 to the plate '56 for horizontal swinging movement inthe same general plane as that of the pointer 90 and the distal end ofthis lever carries a cam member 114 which is preferably in the form of aroller which is received on a pins 115 and rides against the pointer 90in the proximate regions thereof and in the vicinity of the adjustablepivot block 94. Two guide flanges 116 straddle the pointer '90 near saidblock and are carried at the distal end of the lever 110. As shown inFIG. 4, the lever 110 is of the dual link type and is comprised of twoparallel, horizontally extending links 118 which are maintained in theirspaced parallel relationship by a spacer sleeve 120 around the pivot pin1-12. The retracted position of the lever is determined by a limit stop121 which is mounted l(3m the plate 56 and against which the levernormally ears.

A second cam member 122, which likewise may be in the form of a roller,is mounted on a vertical pin 124 on the lever 110 and assumes a medialregion with respect to the latter, this second cam member assuming aposition relatively close to the pivot pin 112 and relatively remotefrom the cam member 1 14. The cam member 122 is designed for directengagement with the central region of the crossbar 24 to which the tierod load indicator is attached.

Although, if desired, the two rollertype cam members 114 and 122 may beloosely mounted on their respective supporting pins so that they arecapable of free rotation thereon. In the illustrated form of theinvention, the two pins are in the form of rivets which fixedly clampthe cam members against rotation so that they make sliding contact withthe pointer and the crossbar respectively rather than tractional rollingcontact.

Referring again to FIG. 1, when the tie rod load indicator 50 of thepresent invention is to be employed for measuring the deflection in agiven crossbar 24, application to the crossbar may be made in either oftwo positions. If the crossbar is positioned in the concrete wall forminstallation 10 at a low elevation where it lies below the level of theeyes of an observer, the indicator will be attached to the crossbar inthe manner previously described with the base part '52 facing upwardlyso that the window opening 82 and the scale 86 may readily be viewed bythe observer. On the other hand, if the crossbar is disposed above thelevel of the eyes of an observer, the indicator 50 will be attached tothe crossbar with the base part 52 facing downwardly where, by lookingupwardly, the scale and pointer mechanism may be conveniently seen. Ineither position of the indicator 50, the roller 122 (FIGS. and 6) willengage the central region of the crossbar for proper magnification bythe mechanism 92 of the deflection of the crossbar when the wet concreteis poured between the opposite sides of the wall form installation.

The present tie rod load indicator makes possible a time-saving methodof pouring wet concrete into a concrete wall form installation havingSteel-Ply or other panels employing crossbars or other transversemembers which are subject to outward deflection or bending incident tooutward bulging of the panel facings under the influence of concretepressure during pouring operations. Assuming that the concrete wall forminstallation 10 of FIG. 1 is of great length, pouring operations may becommenced in the vicinity of the right hand tier of panels 16. Theconcrete is poured between the two panel series '12 and 14 of theinstallation and the Wet concrete falls on the foundation surfacebetween the two panel series 12 and 14 and commences to build up betweenthe two sides of the installation. The lowermost crossbar 24 to whichone of the tie rod load indicators 50 is applied will become outwardlydeflected progressively as the pressure of concrete on the associatedpanel facing increases. It will be understood, of course, that suchdeflection of the selected crossbar will be a direct function of thetension to which the tie rods 18 in the vicinity of such crossbar aresubjected. Thus, outward deflection or bending of the lowermost crossbaroccurs as the concrete is poured and causes the pointer 90 to traversethe window opening 82 and move progressively along the scale 86. Theobserver, by watching the movement of the pointer, may thus ascertainwhen the maximum safe pouring level has been attained and terminateconcrete pouring operations at that time in the particular involvedregion. Such pouring operations may, however, be carried out in otherand remote regions of the concrete wall form installation 10. In a shortperiod of time, usually the time that is consumed by these remotepouring operations, the initially poured concrete will have settled andset or hardened to such an extent that the concrete is then ready tobear an additional load or batch of wet concrete. When this occurs,pouring operations may again be resumed in the vicinity of the firstpouring operation and such concrete as may be piled upon the originallypoured concrete will have no further effect on the pointer 90 of thelowermost tie rod load indicator 50 since the concrete in the vicinityof this apparatus will have hardened. During the second pouringoperation in this particular region of the installation, the next highertie rod load indicator 50 above the first indicator will then be watchedfor crossbar deflection and pouring operations again terminated whenthis second indicator renders an indication that the maximum safe loadon the various adjacent tie rods has been attained. Pouring operationsmay then again be transferred to other remote regions of theinstallation, returning to the able with said lever for maintaining thelatter within of the plate, and a limit stop on said plate andengagepointer in a direction toward said one longitudinal edge indicator50 for the indication of a safe pouring limit for eluding, additionally,a pair of guide flanges carried by said lever adjacent to the distal endthereof and stradd ing region of the lever has mounted thereon a secondcam said pointer for maintaining the pointer and lever in colplanarregister with each other.

the progression of the wall undergoing erection. Thus, a large inventoryof the indicators is not required at the site of any given concrete wallform installation.

The invention is not to be limited to the exact arrangement of partsshown in the accompanying drawings or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit or scope of the invention.

Having thus described the invention what we claim as new and desire tosecure by Letters Patent is:

1. For use in a concrete wall form installation having a wall form panelembodying a panel facing and a crossbar extending horizontally acrossone side of the facing and serving to reinforce said facing, a loadindicator adapted to indicate the deflection of said crossbar under theinfluence of the pressure of wet concrete bearing against the other sideof said facing, said load indicator comprising a rectangular base platehaving inner and outer longitudinal edges and interconnecting transverseend edges, said outer longitudinal edge and said transverse end edgesbeing provided with downturned marginal flanges, thus establishing ashallow tray-like base part, means for releasably clamping the oppositeends of one longitudinal edge of said plate to the end regions of saidcrossbar so that the plate is positioned alongside the crossbar and liesapproximately in the horizontal plane thereof, a pointer having itsproximate end pivoted to said plate at one end region of the latter forswinging movement of the pointer in a horizontal plane across one faceof the plate and within said shallow tray-like base part, and having itsdistal end disposed in traversing relationship with respect to the otherend region of the plate, a scale mounted on said plate and in effectiveregister with said distal end of the pointer for visual indication ofthe position of the pointer, thrust means carried by said plate withinsaid tray-like base part for displacing said pointer throughout an anglecommensurate with the amount of lateral displacement to which thecentral region of the crossbar is subjected when deflection of thecrossbar takes place, said thrust means comprising a lever having itsproximate end pivoted to said plate for swinging movement insubstantially the same horizontal plane as the plane of swingingmovement of the pointer and having its distal end engageable with theproximate and region of the pointer, a medial region of the lever beingslidingly engageable with the central region of the crossbar, and aremovable cover part consisting of a rectangular cover plate withrelatively narrow marginal upturned flanges thereon which aretelescopically received within the confines of the flanges on the baseplate, said base part and cover part thus establishing a generally flatrectangular box-like housing within which the pointer and thrust meansare disposed.

2. A load indicator as set forth in claim 1 and wherein said other endregion of the plate is provided with a Window opening therein and atransparent pane extending across said opening, and said scale isdisposed on said pane and is thus visible through the window opening andpane.

3. A load indicator as set forth in claim 1 and wherein the distal endof said lever has mounted thereon a first cam roller engageable with thepointer and the medial roller engageable with the central region of thecrossbar.

4. A load indicator as set forth in claim 3 and including, additionally,spring means yieldingly urging said ing operations are repetitious,there being one tie rod load 5. A load indicator as set forth in claim 4and inof concrete has become settled and hardened. Such pouroriginalpouring region only when the second lift or batch the rectangularconfines of the plate.

The tie rod load indicator 50 constituting the present invention iscapable of easy removal from its installed position on the associatedcrossbar so that they may be repositioned on the form installationrepeatedly during each concrete lift or batch.

9 10 6. A load indicator as set forth in claim 3 and in- 2,618,15311/1952 McKernan 73-144 eluding, additionally, a guide strap secured tosaid plate, 2,743,607 5/1956 Decker 73-144 extending transverselythereof and across said other end 3,174,334 3/ 1965 McKernan 73144region of the plate, said guide strap, in combination with the adjacentface of the plate, defining a guide slot FOREIGN PATENTS through whichthe distal end region of the pointer pro- 5 1,073,362 96 7 GreatBritain. jects for guiding the pointer in its horizontal plane ofswinging movemgnt. LOUIS I. CAPOZI, Primary Examiner References Cited 10U.S. Cl. X.R. UNITED STATES PATENTS 73144; 116-124 1,306,891 6/1919Grafton 73144 1,591,631 7/19'26 Kennedy 61 a1. 73-144 1,817,203 8/1931Payne 73144 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PatentNo. 3,513,803 May 26, 1970 George F. Bowden et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 7, line 67, beginning with "able with said" cancel all to andincluding "wall form installation." in line 3, of column 8, and insertoriginal pouring region only when the second lift or batch of concretehas become settled and hardened. Such pouring operations arerepetitious, there being one tie rod load indicator 50 for theindication of a safe pouring limit for each concrete lift or batch.

The tie rod load indicator 50 constituting the present invention iscapable of easy removal from its installed position on the associatedcrossbar so that it may be repositioned on the form installationrepeatedly during the progression of the wall undergoing erection. Thus,a large inventory of the indicators 50 is not required at the site ofany given concrete wall form installation.

Column 8, line 45, "and" should read end line 62, after "medial" insertregion of the lever has mounted thereon a second cam same column 8,cancel lines 71 to 75, inclusive.

Signed and sealed this 16th day of February 1971.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting OfficerCommissioner of Patents

